Electrospinning nanofiber membrane has the advantages of wide raw materials, large specific surface area, and high porosity. It is an ideal separator material for lithium-ion batteries. This paper first introduces two common electrospinning nanofiber diaphragms: polymer, polymer, and inorganic composite, and then focuses on the modification methods of composite modification, blending modification, and inorganic modification, as well as the methods of electrospinning nano modified polyolefin diaphragm. Finally, the development direction of the electrospinning lithium-ion battery separator has prospected.

Although public-private partnership (PPP) is regarded as one of the key effective tools in the development of many countries, various challenges surrounding PPPs are not well understood. This paper explores nine key challenges in PPP implementation: (1) different organizational cultures and goals between the partners, (2) poor institutional environment and support, (3) weak political and legal frameworks, (4) unreliable mechanisms for sharing risk and responsibility, (5) inadequate procedures for the selection of PPP partners, (6) inconsistency between resource inputs and quality, (7) inadequate monitoring and evaluation of PPP processes, (8) lack of transparency, and (9) the inherent nature of PPPs. This paper aims to provide the perceptions in the existing literature on many of these challenges, as well as provide solutions to each challenge. 

Using the rank scale rule, taking 47 major port cities in China from 2001 to 2015 as research samples, this paper discusses the rank scale characteristics and hierarchical structure of coastal port city system from a multi-functional perspective, and divides the coupling type of multi-functional development based on shipping logistics. The research shows that: 1) from 2001 to 2015, the scale-free area of manufacturing function order scale distribution in the coastal port city system appeared bifractal structure, the hierarchical segmentation characteristics appeared, and the other functions were single fractal; From the perspective of long-term evolution, only the order and scale distribution of shipping logistics function has developed from centralization to equilibrium, while the business function, manufacturing function (scale-free region I), modern service function and population distribution function are in a centralized situation. 2) The hierarchical structure of coastal port city system has gradually changed from pyramid structure to spindle structure, and generally formed five levels: national hub, regional hub, regional sub center, regional node and local node. 3) From the perspective of multi-functional coupling types, the traditional functions of port cities are generally ahead, while the high-end service functions lag behind, and the improvement speed of urban functions is slow and tends to be flat, indicating that the multi-functional development of China’s coastal port cities is still at a low level, and the industrial system structure needs to be further optimized. 4) From the perspective of port cities at different levels, the functions of regional hub cities and regional sub central cities are in the stage of rapid growth; regional and local node cities are still in the growth stage of traditional functions such as industry and commerce.

Public-Private Partnerships (PPPs) can be an effective way of delivering infrastructure. However, achieving value for money can be difficult if government agencies are not equipped to manage them effectively. Experience from OECD countries shows that the availability of finance is not the main obstacle in delivering infrastructure. Governance—effective decision-making—is the most influential aspect on the quality of an investment, including PPP investments. In 2012, the OECD together with its member countries developed principles to ensure that PPPs deliver value for money transparently and prudently, supported by the right institutional capacities and processes to harness the upside of PPPs without jeopardizing fiscal sustainability. Survey results from OECD countries show that some dimensions of the recommended practices are well applied and past and ongoing reforms show progress. However, other principles have not been well implemented, reflecting the continuing need for improving public governance of PPPs across countries.

Using a newly-developed data set for Portugal, we analyze the industry-level effects of infrastructure investment. Focusing on the divide between traded and non-traded industries, we find that infrastructure investments have a non-traded bias, as these shift the industry mix towards private and public services. We also find that the industries that benefit the most in relative terms are all non-traded: construction, trade, and real estate, among the private services, and education and health, among the public services. Similarly, emerging trading sectors, such as hospitality and professional services, stand to gain. The positive impacts on traded industries are too small to make a difference. These results highlight that infrastructure-based strategies are not neutral in terms of the industry mix. Moreover, with most of the benefits accruing to non-traded industries, such a development model that is heavily based on domestic demand may be unsustainable in light of Portugal’s current foreign account position. 

The provision of infrastructure and related services in developing Asia via public–private partnership (PPP) increased rapidly during the late 1990s. Theoretical arguments support the potential economic benefits of PPPs, but empirical evidence is thin. This paper develops a framework identifying channels through which economic gains can be derived from PPP arrangement. The framework helps derive an empirically tractable specification that examines how PPPs affect the aggregate economy. Empirical results suggest that increasing the ratio of PPP investment to GDP improves access to and quality of infrastructure services, and economic growth will potentially be higher. But this optimism is conditional, especially on the region’s efforts to further upgrade its technical and institutional capacity to handle complex PPP contracts.